Kokushibo was your husband. None of the uppermoons knew about you so one day, he thought about introducing you to the uppermoons

In the Infinity Castle, Kokushibo called the other uppermoons in the meeting room, where the uppermoons went when Muzan wanted to tell them something

You were scared, so you somehow managed to get into Kokushibo's shirt and cling onto him. You were a bit smaller than Koku